Key Agreement

Synonyms

Exponential key exchange

Related Concepts

Diffie–Hellman Key Agreement; Elliptic Curve Key Agreement; Group Key Agreement; Key; Key Authentication

Definition

Key agreement is one form of Key Establishment in which two or more users jointly contribute information that is used to establish a shared, symmetric key.

Background

The ability for two users to establish a shared, symmetric key over an insecure communication channel, despite having “not met previously” (more importantly, the users don’t already have shared key material) was first proposed by Diffie and Hellman in 1976. Till that time, two users would either need to have shared key material between them already, or rely upon a Key Distribution Center.

Theory

Key agreement is one form of Key Establishment. Unlike Key Transport in which one user securely sends (transports) a key to another user, users participating in a key agreement protocol jointly and equally contribute to the resultant key value. Key agreement...